Loud-speaker



June 10, 1930. M. c. H ms 1,763,054

' LOUD SPEAKER Original Filed Jan. '7, 1927 'INVENTORl I Mara); Cffo ak/ns BY I 4 I ATTORNEYS Patented June 10, 1930 UNITED STATES PATENT OFFICE MARCUS C. HOPKINS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO TITANA- FBAM CORPORATION, OF JERSEY CITY, JERSEY, A CORPORATION OF DELA- WARE LOUD-SPEAKER Application filed January 7, 1927, Serial No. 159,554. Renewed April 22, 1930.

formation becomes less apparent and therefore, they are liable to distortion particularly adjacent the outer edge of the cone.

Although the improvement to be herein described is applicable to any diaphragm, which is subject to the above noted obj eetions, it was particularly intended for use in a loud speaker of the type disclosed in my copending application, Serial No. 77,033 filed December 22, 1925. In that application a cone made of relatively light and stiff cover paper is surrounded by a sound board or resonator, there being a flexible connection between the cone and the sound hoard such that the cone responds to the high frequencies and perhaps the intermediate frequencies while the low frequencies are transmitted through the flexible connection to the sound board. In such a device if the outer portion of the cone is liable to distortion, the intermediate frequencies are not accurately reproduced and the low frequencies are not accurately transmitted to the sound board.

The object of the present invention is to so construct the diaphragm as to eliminate any distortion at the places above mentioned. This is accomplished by securing to the diaphragm, near the outer edge thereof, one or more ring like members which act as annular stiffening ribs, each forming a continuous circumferential contact with the face of the diaphragm, and thereby maintaining the diaphragm in true and accurate form. I have found that these stiffening ribs may be made in a simple, inexpensive and practical way by forming them of relatively thin strip material and securing edgewise against the face of the diaphragm. When so made they fully answer the purposes above set forth. I

The preferred embodiment of the invention is illustrated in the accompanying drawing in which I Fig. 1- is a rear view illustrating the diaphragm in assembled relation with the sound-' ing board of a loud speaker unit, and

Fig.2 is an enlarged sectional view thereof.

Fig. 3 is a sectional view of the modification.

Referring to the drawings in detail the improved device comprises a conical diaphragm or tympanum 1, constructed of relatively light and stiff cover paper, being secured around its outer edge, by a flexible connection 2, to a sound board or resonator 3. This is to that used for the construction of the diaphragm 1, and are secured edgewise against the inner-faceof the diaphragm 1 and preferably at right angles thereto as shown in the drawing.

As hereinbefore stated where these conical diaphragms 1 are made in large sizes they lose considerable of the inherent strength and stiffness of the conical shape, resulting in a tendency towards slight distortion at points around the circumference ofthe cone adjacent its outer edge where it is connected at 2 to the sound board 3. r

It will be perfectly obvious that where there is distortion'of any part of the cone a true and accurate regeneration of sound cannot be obtained and as this distortion is more apparent adjacent the outer edge of the cone where the low tones are transmitted to the sound board these low tones will not be reproduced in a true and accurate manner and v it is therefore, at these points adjacent the outer edge of the diaphragm that the annular or ring-like members 4 are secured.

The invention has been described in connection with a conical diaphragm but is equally applicable to any type of substantially conical or flat diaphragm where the same defeet, as above outlined, is apparent and sought to be overcome. The preferred construction as illustrated also shows only two ring-like or annular members 4 but itis within the scope of the present invention to provide any number, more or less, of these members a as the occasion may demand.

' If desired the annular reinforcing memhers 4 may be secured to the convex side of the cone as shown in Fig 3.

What I claim is: 1. In a sound reproducer, the combination 3 with a conical diaphragm, of a series of ringlike members of relatively thin strip material, secured edgewise against the dished face of said cone.

2. In a sound reproducer, the combination as with a conical diaphragm, of a series of ringlike members of relatively thin strip material, secured edgewise against the dished face of said cone and at right angles thereto.

3. In a sound reproducer, the combination so with a conical diaphragm, of a series of ringlike members of relatively thin strip material, secured edgewise against the dished face of said cone, intermediate the apex and base thereof and at right angles thereto.

4. In a sound reproducer, the combination with a conical diaphragm, of a series of ringlike members of relatively thin strip. material, secured edgewise against the dished face of said cone, adjacent the outer edge thereof and at right angles thereto.

5. In a sound reproducer, the combination with a conical diaphragm, of a sound board secured to the outer edge of said diaphragm, a series of ring-like members of relatively thin strip material secured edgewise against the dished face of said conical diaphragm, at right angles thereto and intermediate the apex and base thereof.

6. In a sound reproducer, the'com'bination with a conical diaphragm, of at least one ringlike member of relatively thin strip material secured edgewise against one face of the conical diaphragm intermediate the apex and base thereof and at right angles thereto 7. In a sound reproducer, the combination with a diaphragm of at least one continuous ring-like member of relatively thin strip material secured edgewise against one faceof the diaphragm and at right angles thereto. 50 In testimony whereof Iattix my signature.

MARCUS C. HOPKINS. 

